The Obama administration sent a stern warning to health insurers Monday to not exploit loopholes in healthcare law to not cover preexisting conditions among children.

Health and Human Services Secretary Kathleen Sebelius wrote the head of an insurance industry group, America's Health Insurance Plans (AHIP), warning that she's prepared to issue regulations on top of new healthcare law to ensure children's preexisting conditions are covered.

"Unfortunately, recent media accounts indicate that some insurance companies may be seeking to avoid or ignore a provision in the new law that prohibits insurance companies from excluding children with pre-existing conditions from coverage," Sebelius wrote. 

"To ensure that there is no ambiguity on this point, I am preparing to issue regulations in the weeks ahead ensuring that the term 'pre-existing condition exclusion' applies to both a child's access to a plan and to his or her benefits once he or she is in the plan," the secretary added. 

House Speaker Nancy Pelosi's (D-Calif.) quickly promoted Sebelius's letter on Monday afternoon after having sent their own warnings to insurers this afternoon.